Electrical apparatus



Nov. 17 1925. v I 1,562,143

F. F. BRAND ELECTRICAL APPARATUS Filed July 11. 1921 I Inventor:

Frederick FBr'and by Mir fi His Attor-r1e n rvr Patented Nov. 17, 1925.

UNITED STATES FATENT FREDERICK F. BRAND, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOB TO GENERAL ELECTRIC COMPANY, A CORPORATION Q3? NEYV YORK.

ELECTRICAL Application filed July 11,

T all whom it may concem:

Be it known that I, FREDERICK F. BRAND, a citizen of the United States, residing at Pittsiield, in the county of Berkshire, State of hilassacliusetts, have invented certain new and useful Improven'ients in Electrical Apparatus, of which the following is a specification.

My invention relates to electrical apparatus, and particularly to oil submerged electrical apparatus, and has for its object an improved construction and arrangement of parts which is economical and readily manufactured.

In oil submerged electrical apparatus, such as transformers, some reactors, oil switches and the like, it has been found that the air space above the oil in the casing which houses the apparatus has many disadvantages in addition to making the apparatus bulky and therefore needlessly expensive.

It accordingly has been proposed to eliminate the air space and fill the casing entirely with oil and to take care of the expansion and contraction of the oil content thereof by the provision of an auxiliary tank or casing, generally styled a conservator which is arranged to communicate with the main casing.

Such conservators, according to the best practice, are made not only to keep the air away from the hot 'oil and thereby prevent sludging or rapid oxidation of the oil, but to collect and trap moisture, a special sump being generally provided to this end as taught in the U. S. Letters Patent to Kulka No. 1,002,527.

During internal transient disturbances, such as occur when the windings are short circuited, large quantities of gas are sometimes suddenly generated within this conservator type casing, which, when completely filled with oil, lacks elasticity and is likely to be damaged by the sudden generation of gas attending the transient. To avoid this, it has been the practice generally to provide conservator type casings with relief passages controlled by valves or diaphragms arranged to open or give away and permit the escape of the gas during the transient. Such reliefs,however, have sometimes been found to be inadequate.

In the practice of my invention I propose to remove the need for such a relief by providing the casing with an elastic cushioning APPARATUS.

1921. Serial No. 483,728.

means which will absorb temporarily the initial shock produced by the sudden generation of gas which is likely to damage the casing. A casing thus constructed to embody my invention is able to protect itself against damage by transients, the gas generated being subsequently permitted to escape to the auxiliary casing and thence tov the atmosphere through its usual check valve in a normal manner.

For a more complete understanding of the nature and objects of my invention ref erence should be had to the following detailed description when taken in connection with the accompanying drawing which is a view mainly in vertical section of a con servator type casing for a transformer constructed in accordance with my invention.

Referring now to the drawing, denotes the main casing housing the trans former 11, which casing has the base 12, the cover 13, and auxiliary casing 14 serving as an expansion tank or conservator for the oil or other liquid insulating medium which fills completely the casing 10. Lead insulating bushings are shown mounted on the cover at 15, a breather and a check valve for the conservator being shown respectively at 16 and 17.

In the form of my invention here illus trated, the base 12 is of special construction in order to provide the elastic cushioning means for absorbing tem Jorarily the initial shock of gas generated during a transient. This base is a hollow casing, to which the side walls of the casing 10 are secured. Dcpending from the bottom 20 of the casing 10 is the large tubular nipple 21 which reaches nearly to the bottom of the base 12. This arrangement permits oil to enter from the main casing to fill partially the chamber in the base 12, the remainder of the chamber being filled by air trapped therein, such air being indicated in the space designated at 22 in the draw' ig. A drain of conven tional type for the main casing is shown at 23.

In operation the main casing is filled with oil until the desired height is reached in the conservator which puts the air in the space at 22 under a considerable pressure. Should an internal transient occur and the transformer winding are over, gas would be generated in the oil with explosive force. The trapped air in the space 22 however is elastic. and has a cushioning effect absorbing the energy of the initial shock produced by this sudden generation of gas.

At the termination of the transient the trapped air at 22, which has been further compressed by the transient expands and gently forces the in the main casing to pass over to the auxiliar casing y Way of the passage and out to the atn'iosphere through the check valve 17.

Having now described an embodiment of my invention which is at present the best means known to me for carrying the same into effect, I would have itunderstood that this is merely illustrative and that I do not mean to be limited thereby to the precise details shown nor restricted in the choice of recognized equivalents except as defined in my claim hereunto annexed.

What I claim as new and desire to secure by Letters Patent of the United States, is:

A casing "for electrical apparatus containing a liquid insulating medium, said casing enclosing a compartment for the apparatus and having a base portion providing an ex.- pansion compartment below said apparatus compartment, and means providing communication between said compartments, the insulating liquid extending from said apparatus compartment into and partially filling said expansion compartn'ient.

In Witness whereof, I have hereunto set my hand this 7th day of July, 1921.

FREDERICK .F. BRAND. 

